Cope, Emily K.

Introduction Asthma is a multifactorial disease influenced by genetic and environmental factors, including diet. The gut microbiome contributes to airway inflammation via the gut-lung axis, partly through production of short chain fatty acids (SCFAs) from bacterial fermentation of dietary fiber. We hypothesized that dietary fiber supplementation could modulate the gut microbiome and increase SCFAs in children with asthma. Methods This is a double-blind, placebo-controlled trial of children who were randomized to consume 12 g of soluble corn fiber (SCF) as a supplement to their usual daily diet (50% the recommended daily fiber intake) or placebo for 4–6 weeks ( clinicaltrials.gov NCT03673618). Dietary surveys, asthma symptom questionnaires, fecal, blood and nasal samples were collected before and after the intervention period to quantify fiber intake, asthma control, nasal and gut microbiome, and serum short chain fatty acids (SCFAs). Results Of the 20 children enrolled, 15 completed the intervention with an average adherence rate of 83%. SCFA concentrations and gut microbiome changes varied by individual and treatment group. No significant differences in gut or nasal alpha or beta diversity were observed between groups post-intervention. However, differential abundance analysis showed a trend toward increased Bifidobacterium in the SCF group compared to placebo (ANCOM-BC p = 0.0004, FDR q = 0.073). Discussion Supplementation of 50% of recommended daily fiber intake had minimal impact on asthma symptoms, the microbiome, or SCFA levels. Future studies should consider higher fiber doses, different fiber types, or targeting individuals with low baseline fiber intake to account for observed variability in microbiome and SCFA responses. Clinical Trial Registration https://clinicaltrials.gov/study/NCT03673618 , identifier NCT03673618.

AbstractBackgroundThe role of microbes in chronic rhinosinusitis (CRS) is poorly understood. We hypothesize that analyzing prior microbial exposures via assessing microbial protein serological reactivity in CRS versus controls may offer insights for CRS etiopathogenesis.MethodsWe profiled IgG and IgA antibodies to individual microbial proteins in serum samples of CRS patients and controls using a novel high‐throughput microarray protein technology, Nucleic Acid Programmable Protein Array (NAPPA). The study was conducted on 118 subjects (39 CRS, 79 controls). A CRS‐focused NAPPA array, with 1557 potentially sero‐reactive microbial proteins elected from a pre‐screening of 6500 genes of interest was constructed. It included membrane‐associated proteins from 47 bacterial species and all proteins from 43 viral strains. Differences between CRS and controls were compared across individual antimicrobial antibodies and the species.ResultsChronic rhinosinusitis patients had significantly elevated antimicrobial antibodies compared with controls. One bacterium (Staphylococcus aureus) and three viral strains (human metapneumovirus, human herpesvirus 5, and human herpesvirus 4) were identified as sources of the proteins that showed significantly elevated sero‐reactivity in CRS patients. Within CRS, patients with polyps had elevated antibodies against S. aureus, influenza A virus (H1N1, H3N2), and rhinovirus B14. CRS patients without polyps showed more antibodies against human herpesvirus 1 and vaccinia virus WR.ConclusionsCompared with healthy controls, CRS patients’ serum samples showed significantly increased sero‐reactivity to both bacterial and viral proteins, reflecting recent or current infection or active colonization. Significantly higher antibodies against S. aureus, human metapneumovirus, human herpesvirus 5, and human herpesvirus 4 in CRS need further study.

Background The role of microbiota in sinonasal inflammation can be further understood by targeted sampling of healthy and diseased subjects. We compared the microbiota of the middle meatus (MM) and inferior meatus (IM) in healthy, allergic rhinitis (AR), and chronic rhinosinusitis (CRS) subjects to characterize intrasubject, intersubject, and intergroup differences. Methods Subjects were recruited in the office, and characterized into healthy, AR, and CRS groups. Endoscopically‐guided swab samples were obtained from the MM and IM bilaterally. Bacterial microbiota were characterized by sequencing the V3‐V4 region of the 16S ribosomal RNA (rRNA) gene. Results Intersubject microbiome analyses were conducted in 65 subjects: 8 healthy, 11 AR, and 46 CRS (25 CRS with nasal polyps [CRSwNP]; 21 CRS without nasal polyps [CRSsNP]). Intrasubject analyses were conducted for 48 individuals (4 controls, 11 AR, 8 CRSwNP, and 15 CRSwNP). There was considerable intersubject microbiota variability, but intrasubject profiles were similar ( p = 0.001, nonparametric t test). Intrasubject bacterial diversity was significantly reduced in MM of CRSsNP subjects compared to IM samples ( p = 0.022, nonparametric t test). CRSsNP MM samples were enriched in Streptococcus , Haemophilus , and Fusobacterium spp. but exhibited loss of diversity compared to healthy, CRSwNP, and AR subject‐samples ( p < 0.05; nonparametric t test). CRSwNP patients were enriched in Staphylococcus , Alloiococcus , and Corynebacterium spp. Conclusion This study presents the sinonasal microbiome profile in one of the larger populations of non‐CRS and CRS subjects, and is the first office‐based cohort in the literature. In contrast to healthy, AR, and CRSwNP subjects, CRSsNP MM samples exhibited decreased microbiome diversity and anaerobic enrichment. CRSsNP MM samples had reduced diversity compared to same‐subject IM samples, a novel finding.